1. Field of the Invention
The invention relates generally to analysis and control of equipment used in fabrication facilities and, more particularly, to a method and apparatus for parsing event logs to determine tool operability.
2. Description of the Related Art
Manufacturing facilities, such as semiconductor device manufacturing facilities, commonly employ a series of automated tools. The tools operate in accordance with predetermined scripts, or recipes. Some tools include internal monitoring systems that report various events, including errors, to a tool operator. Typically, these reported events are displayed on a printer or a display screen and/or written to a data file.
One technique for collecting and displaying the conditions of a photolithography stepper tool is described in U.S. Pat. No. 5,757,673, entitled, xe2x80x9cAUTOMATED DATA MANAGEMENT SYSTEM FOR ANALYSIS AND CONTROL OF PHOTOLITHOGRAPHY STEPPER PERFORMANCExe2x80x9d and incorporated herein by reference in its entirety. An exemplary tool capable of reporting various test and error data is a photolithography stepper, such as those available from ASM Lithography, Inc., located in Eindhoven, Netherlands. In this regard, at least one program, in particular, a Virtual Paperless Equipment Logging System hereinafter referred to as xe2x80x9cVPELS,xe2x80x9d has been developed to collect the raw stepper data, save the data to an ASCII file, and periodically upload the ASCII files to a network drive, at which point it may be downloaded and/or printed.
One limitation of such logging systems is their reliance on the operator to identify and respond to error conditions. There is a high volume of log data being generated and displayed (e.g., on a printout or a display) or captured to a data file. Due to the large amount of data continuously being output, it is not uncommon for an operator to miss an error condition that could result in a significant degradation of the operation of the tool. Such degradation, although eventually identifiable through measurements of the downstream processed wafers, may not be identified for a number of runs. Wafers processed in the interim may require rework or they may be scrapped, depending on the nature of the defects.
Compounding the error condition identification problem is the fact that a large amount of the data being logged is routine information regarding tool operation rather than error information. Error conditions can be buried among other routine traffic, making them harder to identify.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
One aspect of the present invention is seen in a method for determining operability of a tool. The method includes generating an event log including a plurality of events associated with the operation of the tool; parsing the event log to identify a crucial event; and initiating an automatic corrective action in response to identifying a crucial event.
Another aspect of the present invention is seen in a manufacturing system including a tool and a tool monitor. The tool is adapted to generate an event log including a plurality of events associated with the operation of the tool. The tool monitor is adapted to parse the event log to identify a crucial event and initiate an automatic corrective action in response to identifying a crucial event.